Resistive superconducting transition and effects of atmospheric exposure in the intercalation superconductor Ax(C2H8N2)yFe2-zSe2 (A = Li, Na)

TL;DR

This study reports the observation of zero-resistivity in intercalation superconductors Ax(C2H8N2)yFe2-zSe2 with Tc of 45 K and finds that the material remains stable under atmospheric exposure for several days.

Contribution

First demonstration of zero-resistivity in Ax(C2H8N2)yFe2-zSe2 superconductors and analysis of their stability against atmospheric exposure.

Findings

Zero-resistivity observed at Tc = 45 K

Normal state resistivity is metallic

Material remains stable under atmospheric exposure for days

Abstract

We have succeeded in observing zero-resistivity in newly discovered intercalation superconductors Ax(C2H8N2)yFe2-zSe2 (A = Li, Na) with Tc = 45 K, using the sintered pellet samples. The electrical resistivity, \r{ho}, in the normal state is metallic and Tconset defined in the $\rho$ measurements, is as high as ~ 57 K. We have also investigated effects of the atmospheric exposure in Lix(C2H8N2)yFe2-zSe2. It has been found that both the crystal structure and superconductivity are maintained at least up to several days, indicating this material is comparatively resistant to the atmospheric exposure.